Apparatus for die drawing large irregularly shaped sheet metal articles



De@ 15, 1936. E. HocHRElT-ERA'ETAL 2,034,160 APPARATUS ECR DIE DRAWING'LARGE IRREGULARLY SHAPED SHEET METAL ARTICLES Filed Dec. :19,l 1951 5sheets-sheet 1 INVENTOR.

EDWARD HQCHREUER l FRANKBNQ GARY- De 15 1935- E. HocHRElTER Er AL2,064,160

APPARATUS FOR DIE DRAWING LARGE IRREGULARLY S'IAPED SHEET METAL.ARTICLES vFiled Dec. 19, 1931 5 Sheets-Sheet 2 23 n Fm INVENTOR. EDWARDHOQHREITEQ. -PRMKBMC'CTARY ATToRNEY.

15, E936. E. Hoge-:REITER ET A1. 2,054,160

APPARATUS FOR DIE DRAWING LARGE IRREGULARLY SHAPED SHEET METAL ARTICLSFiled Dec, 19, 1931 5 Sheets-Sheet 3 l, Il" "I A FRANKEMC-GARY Y BY -M'ZTVEY.

De@ i5 3936 E. HOCHREITER ET AL.' 064,169

APPARATUS FOR DIE DRAWING LARGE IRREGULARL-Y SHAPEDV SHEET METALARTICLES Filed Dec. 19, 1931 s sheds-sheet 4 K 34 y l? 3 36 Fl. l5

1 I l r -IQ 33 :1 -1a?.- 30

l' ll il c l' mo FRANK CGARYl lll BY E M jww 0 ATTORNEY.

Dec. 15, 1936.

. E. HocHRElTER ETAL 2,064,160 APPARATUS FOR DIE DRAWING LARGEIRREGULARLX SHAPED SHEET METAL ARTICLES Filed Dec. 19, 1931 5Sheets-Sheet 5 i8 Y Z Y AFlag/14 M ATTORNEY.

Patented Dec. 15, 1936` )PATENT oFFIcE ArrAnA'rUs ron nm mmwnve.r maar:

IRREGULARLY- SHAPED SHEET METAL ARTICLES Edward Hochreiter and Frank E.McGary, Philadelphia, Pa., assignors to"v Edward G. Budd ManufacturingCo., Philadelphia, Pa., a corporation of Pennsylvania ApplicationDecember 19,1931', Serial No. 582,032

7 Claims. (Cl. 113-46) The invention relates to an apparatus for forminglarge sheet metal stampings of irregular form.

It is a main object of the invention to reduce 5 the cost of formingsuch stampings to improve -their surface and generally to provide anarticle of this class which is superior to the articles heretoforeproduced. In the present application the invention is shown applied tothe formation -of anentire front fenderfincluding the inclined apronjoining the crown of the fender to the body or chassis and thehorizontal ledge bridging the space between this inclined portion andthe body. The crown of the fender is of a double 'horizontal ledge. Inthe region where the curved crown intersects the horizontal ledge, lessmetal is required to form the fender than in it-s forward and rearwardportion, and in previous at tempts to draw the entire fender, ridges andwrinkles have resulted in this region which were impossible of completeremoval, even with expensive operations of hammering and grinding,and-thus marred the entire stamping. Sucha o condition has manifesteditself in other relations,

where the drawwas directed in diiferent directions in different parts ofa. large irregular stamping in regions between such parts, or where theconditions of draw left too much metal in certain regions to be removedwithout wrinkles by the draw in other regions.

The present invention has remediedthis condition., and by the use of ita large irregularly formed'stamping of this class can be produced with asmooth lsurface throughout and with a minimum number of operations. Themain feature of the invention by which these improved results areattained is the use of the step of stretching the metal of the blank ina direction which I 40 will tend to remove the excess metal from theregion likely to produce wrinkles prior to the final forming operation.

The invention also resides in the means whereby this step can be carriedout in proper sequence to the nal forming and with a single die pressoperation.

Other and further objects and advantages will become apparent from thefollowing detailed description of a form of apparatus well adapted tocarry out the method and as used in the formation of complete fenders.

In the accompanying drawings showing the invention applied to the.formation of the diilicult complete fender stampings,

Fig. 1 is a perspective view of a fender stampcurvature, its rearportion dipping below the ing made in accordance with the invention,with the excess metal necessary for the drawing trimmed off. l

Fig. 2 is a central vertical longitudinal sectional view of the fendershown in Fig. l.

Figs. v3 and 4 are transverse sectional views taken respectively on thecorrespondingly numbered lines of Fig. 2.

401. is a transverse section of the fender stamping corresponding to thesection shown in Fig. 4 showing the stamping before trimming randindicating in dotted lines the trim lines.

Fig. 5 is a plan view of an, untrimmed fender stamping indicating theregion in which the wrinkles have heretofore formed, and showing indottedlines the location of the auxiliary die for removing the excessmetal in this region laterally in the drawing operation of the completestamp-s ing.

Fig. 6 is a fragmentary elevational view of a double-action press towhich the invention is shown applied, the dies being shown in separatedposition.

Fig. 7 is a longitudinal vertical sectional view showing the dies andwork in theposition they occupy at the end of the draw.

Fig. 8 is a corresponding View of the parts at lthe beginning of thedraw.

Fig. 9 is an endperspective view, parts being broken away and shown insection, showing the same just prior to the final draw.

Figs. 10, 11, 12, 13 and 14 are corresponding vertical transversesectional views showing successive different positions of the parts,respectively, in the approach movement of the dies.

Fig. 15'is a fragmentary sectional view, looking at the inside face ofthe well or depression in the .lower die showing the parts in theposition indicated in Figs. 7 and 14.

In the drawings', the apparatus for carrying out the improved methodcomprises a double acting press in which A designates generally thelower holding die block, B the upper movable holding die block, C theplunger or ram, D an auxiliary upwardly moving die mounted in the lowerholding die block A and E, a floating stretching die mounted in theupper holding die.

The lower holding die block A is supported in a usual manner upon thebed I0 of a press and has a central well or recess within which lthemovable ram C and die D may be accommodated. Surrounding this well it isprovided with a continuous seat Il adapted to receive the peripheralportion of the blank I2,the seat being generally inclined inwardlytoward the well, as clearly appears in Figs. 7 to 13. Centrally of thewell'is a transverse wall I3 on one side of which is mounted thevertically movable auxiliary die D.

The face I I of the lower holdingV die is provided with recesses |5 andprojecting ribs I6 extending longitudinally-of the seat, and adapted tocooperate with corresponding recesses on the upper holding die to firmlygrip the blank. The depth of lthese ribs and' recesses may vary invarious locations in accordance with the firmness which it is necessaryfor the blank to be held in those locations.

The upper holding die B is supported in a usual manner from thevertically reciprocating head I'I of the press and is provided with aworking face I8 corresponding to the face II of the lower holding die,and between these faces the peripheral portion of the blank is grippedin the nal approach movement of the holding die B, as indicated in Figs.10 to 13. A

The holding die faces conform to the peripheral portion of the blank andare adapted to receive a substantially flat blank located as by pins(not shown) on the lower die, and slots on the edges of the blankadapted to engage the pins.

'Ihe plunger C is designed to eiect the major draw upon the blank and ismounted on a vertically reciprocating head I8 movable independentlyofthe head I'I carrying the upper holding die. In longitudinal sectionlower working face I9 of the plunger C is of a double curvature, con-'forming to the shape of the work to be formed,

and the face is also transversely curved as indicated in Figs. 9 to. 13.l

The lowest point of the plunger face I9 is also the region of thegreatest draw, and the plunger is free to reciprocate vertically througha central opening in the upper holding die block B and into the well ofthe lower holding die block A.

In conformity with the shape of the article, a portion of the draw ismade in the reverse direction from the movement of the plunger C inmaking the main draw, and the means for making this reverse draw is thedie D having an upper face 20 corresponding to the shape of the' articlein the region remote from the end engaged by th lowest portion of theplunger.

The actuating means for this die, as clearly shown in Figs. '7 and 8, isa horizontally sliding cam block 2| mounted in the base of the die blockA and having on its upper face stepped cam faces 22 adapted to coactwith corresponding cam faces 23 on the lower side of the die D. It isguided in its longitudinal movement by gibs 24, and is actuated in thevertical movement of the plunger C by a vertical actuator block 25secured to the head I8 carrying the ram or plunger C, and having aninclined cam face 26 acting on an inclined block 25 engage thecorrespondingly inclined under side of the inwardly extending edgeplungers 2| of the brackets 22 secured to the block 2|.

Between the .front and-rear portions of maxi-v mum draw, there is aregion of minimum draw Aand in this region, as indicated at 21 in Fig.5, the

metal of the blank has, heretofore, been pushed up into wrinkles. Toavoid this objectionable condition, the apparatus of the invention isprovided With means for transversely stretching the metal as indicatedby the arrow b in said figure and to this end, opposite said region ofminimum draw the lower holding die face II is formed with alongitudinally extending recess 28 laterally located between the blankgripping ribs and depressions on the lower and upper holding die faces Iand I8, respectively, and the central well into which the ram Cdescends. The edges of this recess are rounded and the oating die Emounted for vertical movement in the upper dieblock is adapted to haveits lower longitudinally and transversely rounded face 29 descend intothis recess after the blank has been iirmly gripped by the opposedholding die faces II and I 8, and transversely stretch the blank toremove the excess metal in this longitudinal region of the blank priorto the nal die drawing operation, and thus avoid the wrinkling of themetal in this region.

The die E is guided in a vertical slot 30 in the upper holding die blockB and has at its upper end an inclined cam face 3l which is adapted tobe engaged by a corresponding cam face 32 on an actuator block 33 guidedfor transverse movement in the block B, and itself adapted to beactuated by a vertically movable actuator block 34 secured to thevertically reciprocating ram carrying head I8. This actuation is bythe'engagement of a cam face 35 on the lower end of the actuator 34 witha correspondingly inclined cam face 36 on the actuator block 33. Afterthe block 33 has been moved` transversely by the engagement of said camfaces, a vertical face 3'I on the actuator 34 slides in engagement witha corresponding face 38 on the actuator block'33 and maintains it inoperative position during the further descent of the head I8'. Suitablesprings 3 3' act upon the block 33 to move it to inoperative positionafter it is released by the upward movement of the actuator 34.

From the foregoing description of the construction of the improvedapparatus its operation will be readily understood from the followingdescription of its operation when read in connection with the variousiigures of the drawings showing different successive stages of theoperation.

A flat metal sheet roughly of the peripheral contour shown in the planview of Fig. 5 is ilrst placed over the lower holding die A with-itsperipheral portion resting on the face II of the lower holding die whilethe parts of the press are in the position shown in Figs. 6 and 10.

'I'he press is then operated to cause the upper holding die B to descendand grip the margin of the blank between the mating faces II and I8,

respectively, of the lower and upper holding dies, as shown in Fig. 11.

After the' sheet is grasped by the holding dies,

the lowest portion of the ram C strikes the sheet and starts the drawingoperation in thev region of the deepest drawat the front of the fenderblank `n1ediate the front and rear deeply drawn portions of. the blank,all as clearly shown in the figures of the drawings above referred to.

The metal of the blank will thus be simultaneously subjected to drawingstrains in the three directions indicated by the arrows a, b and c ofFig. 5.

In the final drawing movement of the dies C and D, a longitudinallyextending raised projection 40 at the side of the ram in thelongitudinal region of the minimum draw opposite the stretching dieEengages the blank and depresses it into a corresponding recess 4| in thelower holding die face and thus further transversely stretches the blankin this region and at the sam-e time the entire blank is given the finaldrawing, which is completed when the parts reach the position shown inFig. 7, when the blank is nally formed.

By so transversely stretching themetal of. the blank transverselythrough die E and projection 40 in the intermediate region of minimumdraw,

while subjecting the opposite ends thereof to rela' er stamping shown inFigs. 1 and 2 produced from a fiat blank at one operation of the press.

After the stamping has been formed the movable dies recede to thepositions-shown in Figs.

6 and 10, and the stamping is removed from the press and subsequentlytrimmed along the dotted lines indicated in Figs. 4a and 5 to producethe finished complete fender shown in Figs. 1 and 2.

The operation of. forming the stampings can proceed as rapidly as thepress operation permits, a complete fender being formed at eachoperation.

While the invention has been shown and de- -scribed in connection withthe manufacture of complete fenders, it will be understood that theoutstanding feature thereof, namely, the stretching of the metal of theblank to remove excess metal from a region of minimum draw may bepracticed in connection with the formation of irregularly shapedstampngs of .other forms and the particular structure of the apparatusby which this is achieved may be varied to suit the conditions of theparticular forrl. of stamping being made, without departing from thegeneric spirit of the invention as expressed in the claims appendedhereto.

What we claim is: l

1. Apparatus for die stamping large irregularly shaped sheet metalarticles comprising means for' rigidly clampmg .the side and end edgesof. an elongated blank, means independent of said clamping means forsubstantially stretching the blank transversely of its length in theplane of the blank when so clampedr and Ameans for die drawing theblank, when so stretched and rigidly held, movable generallytransversely to the plane of the blank.

2. Apparatus for die drawing sheet metal articles of irregular formwhich consists of a bed having surfaces upon which the peripheralmargins of the blank are adapted to rest, means covacting with saidsurfaces to clamp the margins in place, a die movable generallytransversely to the sheet for drawing and shaping it, and a stretchingdie independent of the clamping meansto the iinal drawing of the blankto the required form.

3. Apparatus for die drawing sheet metal fenders comprising clampingmeans for holding the side and end peripheral portions of an elongated.

blank, a punch movable within said clamping means generally transverselyto `the plane of the blank to form the same, and a die actuatedindependently of the clampingmeans `in the movement of said punch for-engaging a peripheral portion of the blank and thereby substantiallystretching the metal of the blank transversely in a' region of minimumdraw prior to the final drawing movement of the punch.

4. Apparatus for die drawing sheet metal fenders comprising albed havinga-peripheral surface adapted to receive the margins of the blank, and awell within said surface, a die mounted in said bed for upward movement,a punch adapted for downward movement into said well, means associatedwith said punch for moving the said die upwardly while the punch movesdownwardly to draw the metal of the blank in opposite directions atopposite ends thereof.

5. Apparatus for die drawing sheet metal fenders comprising a lower diehaving a peripheral surface for receivingthe marginal portion of theblank, and a central hollow well, a vertically movable die adjacent oneend of the well and a vertically. movable ram, a. clamping diesurrounding the ram and movable to clamp the marginal portion of theblank between it and the peripheral surface of said first-named die, avertically movable stretching die for stretching the blank in a regionof minimum draw mounted in said clamping die, and means associated withsaid ram for actuatingsaid stretching die and the vertically movable diein the approach movement of the ram for forming the blank.

6.` Apparatus for die drawing sheet metal articles of irregular'formwhich consists of' lateral and end hold down surfaces, a hold down Idiegripping the metal-of a blank between it and said surfaces and leaving acentral portion free to be drawn, a movable -drawing die movable intoengagement with the` sheet to form it, and a stretching die movableindependently of the hold-down die to substantially stretch the blank ina region of minimum draw engaged by means associated with the drawingdie prior to the nal drawing movement of the drawing die.

'7. Apparatus for'die drawing large irregularly of an elongated blank, amain plunger for drawing the metal of the blank in one direction to themaximum depth of draw, an auxiliary plunger cooperating with the mainplunger for drawing the metal independently of the vholding dies from aregion of minimum draw simultaneously with the drawing operation of themain plunger to remove excess metal from said region of minimum draw andprevent the formation of Wrinkles in the final stroke of the apparatus,and means for operating said parts in properly synchronized relation.

EDWARD VHOCHREITER, FRANK E. MCGARY.

